1. Field of the Invention
The present invention relates to an electronic apparatus with a wireless unit.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2001-160788 discloses a notebook personal computer with a card slot, which can change the spreading rate of a spread spectrum clock generator (SSCG) based on information provided from a wireless unit mounted on the card slot.
Japanese Patent Laid-Open No. 2003-256069 discloses a recording apparatus in which an operating current of a central processing unit (CPU) that controls an electronic apparatus is detected, and an operating load on the CPU is determined based on the current. If the operating load is high, a multiplication factor is increased to increase the operating frequency of the CPU. If the operating load is low, the multiplication factor is reduced to reduce the operating frequency of the CPU.
Japanese Patent Laid-Open No. 2003-248524 discloses a large-scale integrated circuit (LSI) that can operate in a plurality of operating modes including a mode where the LSI operates at a relatively high frequency and a mode where the LSI operates at a relatively low frequency. Low power consumption of the LSI is achieved by dynamically and quickly controlling a clock state.
Japanese Patent Laid-Open No. 2001-160788 has a description of a single wireless unit that is mounted on the card slot of the personal computer, but has no description of use of a plurality of wireless units having different operating frequencies.
In Japanese Patent Laid-Open No. 2003-256069, the operating frequency is changed according to the load on the CPU. Therefore, a clock signal has different frequencies when multiple operations including wireless communication and recording are performed in parallel and when only wireless communication is performed. Thus, the level of electromagnetic interference (EMI) noise cannot be determined only based on the amount of load on the CPU. It is therefore difficult to suppress EMI noise in accordance with various states of the electronic apparatus.